Efficient conversion of fluorinated greenhouse gases using aluminum-doped hydroxyapatite

Abstract

In this study, a series of hydroxyl apatite catalysts (HA-xAl) with varying aluminum doping levels were synthesized using a hydrothermal method. The influence of aluminum doping on the activity and catalytic stability of HFC-152a dehydrofluorination was systematically investigated. Reaction rates were normalized according to the aluminum doping amount. The results revealed that the HA-5Al catalyst exhibited a high specific reaction rate of 16,500 mmol·h⁻¹ ·mol⁻¹ Al, indicating a significant enhancement in catalytic efficiency due to aluminum incorporation into the hydroxyapatite. Furthermore, the HA-20Al catalyst demonstrated a conversion exceeding 63 % after 100 h of reaction. This remarkable stability is attributed to the formation of a metastable active species, F-Al-O, which likely results from the limited interaction with the hydroxyapatite structure. Additionally, the optimal acidity and highly dispersed active sites of catalysts contribute to reduced carbon deposition and further enhance its stability.